Method and apparatus for transmitting/receiving wireless signal in wireless communication system

ABSTRACT

According to an embodiment of the present invention a UE may receive a first system information block (SIB) including a system information (SI) request-related configuration including a physical random access channel configuration; transmit a random access (RA) preamble for an SI request based on the PRACH configuration; and receive, in response to the RA preamble, a second SIB different from the first SIB, wherein the SI request-related configuration may include first information related only to a first type UE with reduced capability to support a smaller bandwidth than a second type UE, and second information common for the first type UE and the second type UE, and the UE may be the first type UE and may perform the RA preamble transmission by determining an RA association period and an RA occasion based on both of the first information and the second information in the SI request-related configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application No.10-2020-0132970, filed on Oct. 14, 2020, which is hereby incorporated byreference as if fully set forth herein.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for transmitting/receivinga wireless signal.

BACKGROUND

Generally, a wireless communication system is developing to diverselycover a wide range to provide such a communication service as an audiocommunication service, a data communication service and the like. Thewireless communication is a sort of a multiple access system capable ofsupporting communications with multiple users by sharing availablesystem resources (e.g., bandwidth, transmit power, etc.). For example,the multiple access system may be any of a code division multiple access(CDMA) system, a frequency division multiple access (FDMA) system, atime division multiple access (TDMA) system, an orthogonal frequencydivision multiple access (OFDMA) system, and a single carrier frequencydivision multiple access (SC-FDMA) system.

SUMMARY

An object of the present disclosure is to provide a method ofefficiently performing wireless signal transmission/reception proceduresand an apparatus therefor.

It will be appreciated by persons skilled in the art that the objectsand advantages that could be achieved with the present disclosure arenot limited to what has been particularly described hereinabove and theabove and other objects and advantages that the present disclosure couldachieve will be more clearly understood from the following detaileddescription.

In an aspect of the present invention, a method of receiving a signal bya user equipment (UE) in a wireless communication system, may comprise:receiving a first system information block (SIB) including a systeminformation (SI) request-related configuration including a physicalrandom access channel (PRACH) configuration; transmitting a randomaccess (RA) preamble for an SI request based on the PRACH configuration;and receiving, in response to the RA preamble for the SI request, asecond SIB different from the first SIB, wherein the SI request-relatedconfiguration may include first information related only to a first typeUE with reduced capability to support a smaller bandwidth (BW) than asecond type UE, and second information that is common for the first typeUE and the second type UE, and wherein the UE may be the first type UEand may perform the RA preamble transmission by determining a specificRA association period and a specific RA occasion (RO) based on both ofthe first information and the second information in the SIrequest-related configuration.

The first information may include an RA association period index, andthe second information may include an SI request period. The SI requestperiod may include one or more RA association periods and the RAassociation period index may indicate the specific RA association periodfrom the one or more RA association periods in the SI request period.Each RA association period may denote a minimum number of PRACHconfiguration periods required for every synchronization signal block(SSB) to be associated with a corresponding RO at least once. Thespecific RA association period may be dedicated to the first type UE,and the SI request period may be shared between the first type UE andthe second type UE.

The first information may include information regarding the specific RO,and the second information may include an RA association period indexand an SI request period. The specific RO may be dedicated to the firsttype UE and the specific RA association period may be shared between thefirst type UE and the second type UE.

The first information may include an SI request period. A first SIrequest period may be configured for the first type UE and a second SIrequest period may be configured for the second type UE. The specific RAassociation period may be one of RA association periods included in thefirst SI request period.

The first SIB may be an SIB common for the first type UE and the secondtype UE, and the second SIB may be an SIB dedicated to the first typeUE.

The first SIB may be SIB1 and the second SIB may be SIBx, where ‘x’denotes an integer larger than 1.

According to other aspect of the present invention, a non-transitorycomputer readable medium recorded thereon program codes for performingthe aforementioned method is presented.

According to another aspect of the present invention, the UE configuredto perform the aforementioned method is presented.

According to another aspect of the present invention, a deviceconfigured to control the UE to perform the aforementioned method ispresented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates physical channels used in a 3rd generationpartnership project (3GPP) system, which is an example of wirelesscommunication systems, and a general signal transmission method usingthe same;

FIG. 2 illustrates a radio frame structure;

FIG. 3 illustrates a resource grid of a slot;

FIG. 4 illustrates exemplary mapping of physical channels in a slot;

FIG. 5 is a diagram illustrating a signal flow for a physical downlinkcontrol channel (PDCCH) transmission and reception process;

FIG. 6 illustrates exemplary multi-beam transmission of an SSB;

FIG. 7 illustrates an exemplary method of indicating an actuallytransmitted SSB;

FIG. 8 illustrates an example of PRACH transmission in the NR system;

FIG. 9 illustrates an example of a RACH occasion defined in one RACHslot in the NR system;

FIG. 10 illustrates an SIBx or R-SIBx request process of N-UE and R-UEaccording to an embodiment of the present invention.

FIG. 11 illustrates a method of receiving a signal by a user equipmentin an embodiment of the present invention;

FIG. 12 to FIG. 15 illustrate a communication system 1 and wirelessdevices applied to the present disclosure; and

FIG. 16 illustrates an exemplary discontinuous reception (DRX) operationapplied to the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure are applicable to a variety ofwireless access technologies such as code division multiple access(CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), and single carrier frequency division multiple access(SC-FDMA). CDMA can be implemented as a radio technology such asUniversal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can beimplemented as a radio technology such as Global System for Mobilecommunications (GSM)/General Packet Radio Service (GPRS)/Enhanced DataRates for GSM Evolution (EDGE). OFDMA can be implemented as a radiotechnology such as Institute of Electrical and Electronics Engineers(IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwideinteroperability for Microwave Access (WiMAX)), IEEE 802.20, and EvolvedUTRA (E-UTRA). UTRA is a part of Universal Mobile TelecommunicationsSystem (UMTS). 3rd Generation Partnership Project (3GPP) Long TermEvolution (LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA, andLTE-Advanced (A) is an evolved version of 3GPP LTE. 3GPP NR (New Radioor New Radio Access Technology) is an evolved version of 3GPP LTE/LTE-A.

As more and more communication devices require a larger communicationcapacity, there is a need for mobile broadband communication enhancedover conventional radio access technology (RAT). In addition, massiveMachine Type Communications (MTC) capable of providing a variety ofservices anywhere and anytime by connecting multiple devices and objectsis another important issue to be considered for next generationcommunications. Communication system design considering services/UEssensitive to reliability and latency is also under discussion. As such,introduction of new radio access technology considering enhanced mobilebroadband communication (eMBB), massive MTC, and Ultra-Reliable and LowLatency Communication (URLLC) is being discussed. In the presentdisclosure, for simplicity, this technology will be referred to as NR(New Radio or New RAT).

For the sake of clarity, 3GPP NR is mainly described, but the technicalidea of the present disclosure is not limited thereto.

Details of the background, terminology, abbreviations, etc. used hereinmay be found in 3GPP standard documents published before the presentdisclosure.

Following documents are incorporated by reference:

3GPP LTE

-   -   TS 36.211: Physical channels and modulation    -   TS 36.212: Multiplexing and channel coding    -   TS 36.213: Physical layer procedures    -   TS 36.300: Overall description    -   TS 36.321: Medium Access Control (MAC)    -   TS 36.331: Radio Resource Control (RRC)

3GPP NR

-   -   TS 38.211: Physical channels and modulation    -   TS 38.212: Multiplexing and channel coding    -   TS 38.213: Physical layer procedures for control    -   TS 38.214: Physical layer procedures for data    -   TS 38.300: NR and NG-RAN Overall Description    -   TS 38.321: Medium Access Control (MAC)    -   TS 38.331: Radio Resource Control (RRC) protocol specification

Abbreviations and Terms

-   -   PDCCH: Physical Downlink Control CHannel    -   PDSCH: Physical Downlink Shared CHannel    -   PUSCH: Physical Uplink Shared CHannel    -   CSI: Channel state information    -   RRM: Radio resource management    -   RLM: Radio link monitoring    -   DCI: Downlink Control Information    -   CAP: Channel Access Procedure    -   Ucell: Unlicensed cell    -   PCell: Primary Cell    -   PSCell: Primary SCG Cell    -   TBS: Transport Block Size    -   SLIV: Starting and Length Indicator Value    -   BWP: BandWidth Part    -   CORESET: COntrol REsourse SET    -   REG: Resource element group    -   SFI: Slot Format Indicator    -   COT: Channel occupancy time    -   SPS: Semi-persistent scheduling    -   PLMN ID: Public Land Mobile Network identifier    -   RACH: Random Access Channel    -   RAR: Random Access Response    -   Msg3: Message transmitted on UL-SCH containing a C-RNTI MAC CE        or CCCH SDU, submitted from upper layer and associated with the        UE Contention Resolution Identity, as part of a Random Access        procedure.    -   Special Cell: For Dual Connectivity operation the term Special        Cell refers to the PCell of the MCG or the PSCell of the SCG        depending on if the MAC entity is associated to the MCG or the        SCG, respectively. Otherwise the term Special Cell refers to the        PCell. A Special Cell supports PUCCH transmission and        contention-based Random Access, and is always activated.    -   Serving Cell: A PCell, a PSCell, or an SCell

In a wireless communication system, a user equipment (UE) receivesinformation through downlink (DL) from a base station (BS) and transmitinformation to the BS through uplink (UL). The information transmittedand received by the BS and the UE includes data and various controlinformation and includes various physical channels according totype/usage of the information transmitted and received by the UE and theBS.

FIG. 1 illustrates physical channels used in a 3GPP NR system and ageneral signal transmission method using the same.

When a UE is powered on again from a power-off state or enters a newcell, the UE performs an initial cell search procedure, such asestablishment of synchronization with a BS, in step S101. To this end,the UE receives a synchronization signal block (SSB) from the BS. TheSSB includes a primary synchronization signal (PSS), a secondarysynchronization signal (SSS), and a physical broadcast channel (PBCH).The UE establishes synchronization with the BS based on the PSS/SSS andacquires information such as a cell identity (ID). The UE may acquirebroadcast information in a cell based on the PBCH. The UE may receive aDL reference signal (RS) in an initial cell search procedure to monitora DL channel status.

After initial cell search, the UE may acquire more specific systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving a physical downlink shared channel (PDSCH) based oninformation of the PDCCH in step S102.

The UE may perform a random access procedure to access the BS in stepsS103 to S106. For random access, the UE may transmit a preamble to theBS on a physical random access channel (PRACH) (S103) and receive aresponse message for preamble on a PDCCH and a PDSCH corresponding tothe PDCCH (S104). In the case of contention-based random access, the UEmay perform a contention resolution procedure by further transmittingthe PRACH (S105) and receiving a PDCCH and a PDSCH corresponding to thePDCCH (S106).

After the foregoing procedure, the UE may receive a PDCCH/PDSCH (S107)and transmit a physical uplink shared channel (PUSCH)/physical uplinkcontrol channel (PUCCH) (S108), as a general downlink/uplink signaltransmission procedure. Control information transmitted from the UE tothe BS is referred to as uplink control information (UCI). The UCIincludes hybrid automatic repeat and requestacknowledgement/negative-acknowledgement (HARQ-ACK/NACK), schedulingrequest (SR), channel state information (CSI), etc. The CSI includes achannel quality indicator (CQI), a precoding matrix indicator (PMI), arank indicator (RI), etc. While the UCI is transmitted on a PUCCH ingeneral, the UCI may be transmitted on a PUSCH when control informationand traffic data need to be simultaneously transmitted. In addition, theUCI may be aperiodically transmitted through a PUSCH according torequest/command of a network.

FIG. 2 illustrates a radio frame structure. In NR, uplink and downlinktransmissions are configured with frames. Each radio frame has a lengthof 10 ms and is divided into two 5-ms half-frames (HF). Each half-frameis divided into five 1-ms subframes (SFs). A subframe is divided intoone or more slots, and the number of slots in a subframe depends onsubcarrier spacing (SCS). Each slot includes 12 or 14 OrthogonalFrequency Division Multiplexing (OFDM) symbols according to a cyclicprefix (CP). When a normal CP is used, each slot includes 14 OFDMsymbols. When an extended CP is used, each slot includes 12 OFDMsymbols.

Table 1 exemplarily shows that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varyaccording to the SCS when the normal CP is used.

TABLE 1 SCS (15 * 2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3)  14 80 8 240 KHz (u = 4)  14 160 16*N^(slot) _(symb): Number of symbols in a slot *N^(frame,u) _(slot):Number of slots in a frame *N^(subframe,u) _(slot): Number of slots in asubframe

Table 2 illustrates that the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe vary according tothe SCS when the extended CP is used.

TABLE 2 SCS (15 * 2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

The structure of the frame is merely an example. The number ofsubframes, the number of slots, and the number of symbols in a frame mayvary.

In the NR system, OFDM numerology (e.g., SCS) may be configureddifferently for a plurality of cells aggregated for one UE. Accordingly,the (absolute time) duration of a time resource (e.g., an SF, a slot ora TTI) (for simplicity, referred to as a time unit (TU)) consisting ofthe same number of symbols may be configured differently among theaggregated cells. Here, the symbols may include an OFDM symbol (or aCP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbol).

FIG. 3 illustrates a resource grid of a slot. A slot includes aplurality of symbols in the time domain. For example, when the normal CPis used, the slot includes 14 symbols. However, when the extended CP isused, the slot includes 12 symbols. A carrier includes a plurality ofsubcarriers in the frequency domain. A resource block (RB) is defined asa plurality of consecutive subcarriers (e.g., 12 consecutivesubcarriers) in the frequency domain. A bandwidth part (BWP) may bedefined to be a plurality of consecutive physical RBs (PRBs) in thefrequency domain and correspond to a single numerology (e.g., SCS, CPlength, etc.). The carrier may include up to N (e.g., 5) BWPs. Datacommunication may be performed through an activated BWP, and only oneBWP may be activated for one UE. In the resource grid, each element isreferred to as a resource element (RE), and one complex symbol may bemapped to each RE.

FIG. 4 illustrates exemplary mapping of physical channels in a slot. Inthe NR system, a DL control channel, DL or UL data, and a UL controlchannel may be included in one slot. For example, the first N symbols(hereinafter, referred to as a DL control region) of a slot may be usedto transmit a DL control channel (e.g., PDCCH), and the last M symbols(hereinafter, referred to as a UL control region) of the slot may beused to transmit a UL control channel (e.g., PUCCH). Each of N and M isan integer equal to or larger than 0. A resource region (hereinafter,referred to as a data region) between the DL control region and the ULcontrol region may be used to transmit DL data (e.g., PDSCH) or UL data(e.g., PUSCH). A guard period (GP) provides a time gap for transmissionmode-to-reception mode switching or reception mode-to-transmission modeswitching at a BS and a UE. Some symbol at the time of DL-to-ULswitching in a subframe may be configured as a GP.

The PDCCH delivers DCI. For example, the PDCCH (i.e., DCI) may carryinformation about a transport format and resource allocation of a DLshared channel (DL-SCH), resource allocation information of an uplinkshared channel (UL-SCH), paging information on a paging channel (PCH),system information on the DL-SCH, information on resource allocation ofa higher-layer control message such as an RAR transmitted on a PDSCH, atransmit power control command, information about activation/release ofconfigured scheduling, and so on. The DCI includes a cyclic redundancycheck (CRC). The CRC is masked with various identifiers (IDs) (e.g. aradio network temporary identifier (RNTI)) according to an owner orusage of the PDCCH. For example, if the PDCCH is for a specific UE, theCRC is masked by a UE ID (e.g., cell-RNTI (C-RNTI)). If the PDCCH is fora paging message, the CRC is masked by a paging-RNTI (P-RNTI). If thePDCCH is for system information (e.g., a system information block(SIB)), the CRC is masked by a system information RNTI (SI-RNTI). Whenthe PDCCH is for an RAR, the CRC is masked by a random access-RNTI(RA-RNTI).

FIG. 5 is a diagram illustrating a signal flow for a PDCCH transmissionand reception process.

Referring to FIG. 5 , a BS may transmit a control resource set (CORESET)configuration to a UE (S502). A CORSET is defined as a resource elementgroup (REG) set having a given numerology (e.g., an SCS, a CP length,and so on). An REG is defined as one OFDM symbol by one (P)RB. Aplurality of CORESETs for one UE may overlap with each other in thetime/frequency domain. A CORSET may be configured by system information(e.g., a master information block (MIB)) or higher-layer signaling(e.g., radio resource control (RRC) signaling). For example,configuration information about a specific common CORSET (e.g., CORESET#0) may be transmitted in an MIB. For example, a PDSCH carrying systeminformation block 1 (SIB1) may be scheduled by a specific PDCCH, andCORSET #0 may be used to carry the specific PDCCH. Configurationinformation about CORESET #N (e.g., N>0) may be transmitted by RRCsignaling (e.g., cell-common RRC signaling or UE-specific RRCsignaling). For example, the UE-specific RRC signaling carrying theCORSET configuration information may include various types of signalingsuch as an RRC setup message, an RRC reconfiguration message, and/or BWPconfiguration information. Specifically, a CORSET configuration mayinclude the following information/fields.

-   -   controlResourceSetId: indicates the ID of a CORESET.    -   frequencyDomainResources: indicates the frequency resources of        the CORESET. The frequency resources of the CORESET are        indicated by a bitmap in which each bit corresponds to an RBG        (e.g., six (consecutive) RBs). For example, the most significant        bit (MSB) of the bitmap corresponds to a first RBG. RBGs        corresponding to bits set to 1 are allocated as the frequency        resources of the CORESET.    -   duration: indicates the time resources of the CORESET. Duration        indicates the number of consecutive OFDM symbols included in the        CORESET. Duration has a value of 1 to 3.    -   cce-REG-MappingType: indicates a control channel element        (CCE)-REG mapping type. Interleaved and non-interleaved types        are supported.    -   interleaverSize: indicates an interleaver size.    -   pdcch-DMRS-ScramblingID: indicates a value used for PDCCH DMRS        initialization. When pdcch-DMRS-ScramblingID is not included,        the physical cell ID of a serving cell is used.    -   precoderGranularity: indicates a precoder granularity in the        frequency domain.    -   reg-BundleSize: indicates an REG bundle size.    -   tci-PresentInDCI: indicates whether a transmission configuration        index (TCI) field is included in DL-related DCI.    -   tci-StatesPDCCH-ToAddList: indicates a subset of TCI states        configured in pdcch-Config, used for providing quasi-co-location        (QCL) relationships between DL RS(s) in an RS set (TCI-State)        and PDCCH DMRS ports.

Further, the BS may transmit a PDCCH search space (SS) configuration tothe UE (S504). The PDCCH SS configuration may be transmitted byhigher-layer signaling (e.g., RRC signaling). For example, the RRCsignaling may include, but not limited to, various types of signalingsuch as an RRC setup message, an RRC reconfiguration message, and/or BWPconfiguration information. While a CORESET configuration and a PDCCH SSconfiguration are shown in FIG. 5 as separately signaled, forconvenience of description, the present disclosure is not limitedthereto. For example, the CORESET configuration and the PDCCH SSconfiguration may be transmitted in one message (e.g., by one RRCsignaling) or separately in different messages.

The PDCCH SS configuration may include information about theconfiguration of a PDCCH SS set. The PDCCH SS set may be defined as aset of PDCCH candidates monitored (e.g., blind-detected) by the UE. Oneor more SS sets may be configured for the UE. Each SS set may be a USSset or a CSS set. For convenience, PDCCH SS set may be referred to as“SS” or “PDCCH SS”.

A PDCCH SS set includes PDCCH candidates. A PDCCH candidate is CCE(s)that the UE monitors to receive/detect a PDCCH. The monitoring includesblind decoding (BD) of PDCCH candidates. One PDCCH (candidate) includes1, 2, 4, 8, or 16 CCEs according to an aggregation level (AL). One CCEincludes 6 REGs. Each CORESET configuration is associated with one ormore SSs, and each SS is associated with one CORESET configuration. OneSS is defined based on one SS configuration, and the SS configurationmay include the following information/fields.

-   -   searchSpaceId: indicates the ID of an SS.    -   controlResourceSetId: indicates a CORESET associated with the        SS.    -   monitoringSlotPeriodicityAndOffset: indicates a periodicity (in        slots) and offset (in slots) for PDCCH monitoring.    -   monitoringSymbolsWithinSlot: indicates the first OFDM symbol(s)        for PDCCH monitoring in a slot configured with PDCCH monitoring.        The first OFDM symbol(s) for PDCCH monitoring is indicated by a        bitmap with each bit corresponding to an OFDM symbol in the        slot. The MSB of the bitmap corresponds to the first OFDM symbol        of the slot. OFDM symbol(s) corresponding to bit(s) set to 1        corresponds to the first symbol(s) of a CORESET in the slot.    -   nrofCandidates: indicates the number of PDCCH candidates (one of        values 0, 1, 2, 3, 4, 5, 6, and 8) for each AL where AL={1, 2,        4, 8, 16}.    -   searchSpaceType: indicates common search space (CSS) or        UE-specific search space (USS) as well as a DCI format used in        the corresponding SS type.

Subsequently, the BS may generate a PDCCH and transmit the PDCCH to theUE (S506), and the UE may monitor PDCCH candidates in one or more SSs toreceive/detect the PDCCH (S508). An occasion (e.g., time/frequencyresources) in which the UE is to monitor PDCCH candidates is defined asa PDCCH (monitoring) occasion. One or more PDCCH (monitoring) occasionsmay be configured in a slot.

Table 3 shows the characteristics of each SS.

TABLE 3 Search Type Space RNTI Use Case Type0-PDCCH Common SI-RNTI on aprimary SIB Decoding cell Type0A-PDCCH Common SI-RNTI on a primary SIBDecoding cell Type1-PDCCH Common RA-RNTI or TC-RNTI Msg2, Msg4 on aprimary cell decoding in RACH Type2-PDCCH Common P-RNTI on a primaryPaging cell Decoding Type3-PDCCH Common INT-RNTI, SFI-RNTI,TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI, C-RNTI, MCS-C-RNTI, orCS-RNTI(s) UE C-RNTI, or User specific Specific MCS-C-RNTI, PDSCH orCS-RNTI(s) decoding

Table 4 shows DCI formats transmitted on the PDCCH.

TABLE 4 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of PUSCH in one cell 1_0 Scheduling of PDSCH in one cell 1_1Scheduling of PDSCH in one cell 2_0 Notifying a group of UEs of the slotformat 2_1 Notifying a group of UEs of the PRB(s) and OFDM symbol(s)where UE may assume no transmission is intended for the UE 2_3Transmission of a group of TPC commands for SRS transmissions by one ormore UEs

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH,and DCI format 0_1 may be used to schedule a TB-based (or TB-level)PUSCH or a code block group (CBG)-based (or CBG-level) PUSCH. DCI format1_0 may be used to schedule a TB-based (or TB-level) PDSCH, and DCIformat 1_1 may be used to schedule a TB-based (or TB-level) PDSCH or aCBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0/0_1 may bereferred to as UL grant DCI or UL scheduling information, and DCI format1_0/1_1 may be referred to as DL grant DCI or DL scheduling information.DCI format 2_0 is used to deliver dynamic slot format information (e.g.,a dynamic slot format indicator (SFI)) to a UE, and DCI format 2_1 isused to deliver DL pre-emption information to a UE. DCI format 2_0and/or DCI format 2_1 may be delivered to a corresponding group of UEson a group common PDCCH which is a PDCCH directed to a group of UEs.

DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCIformats, whereas DCI format 0_1 and DCI format 1_1 may be referred to asnon-fallback DCI formats. In the fallback DCI formats, a DCI size/fieldconfiguration is maintained to be the same irrespective of a UEconfiguration. In contrast, the DCI size/field configuration variesdepending on a UE configuration in the non-fallback DCI formats.

A CCE-to-REG mapping type is set to one of an interleaved type and anon-interleaved type.

-   -   Non-interleaved CCE-to-REG mapping (or localized CCE-to-REG        mapping): 6 REGs for a given CCE are grouped into one REG        bundle, and all of the REGs for the given CCE are contiguous.        One REG bundle corresponds to one CCE.    -   Interleaved CCE-to-REG mapping (or distributed CCE-to-REG        mapping): 2, 3 or 6 REGs for a given CCE are grouped into one        REG bundle, and the REG bundle is interleaved within a CORESET.        In a CORESET including one or two OFDM symbols, an REG bundle        includes 2 or 6 REGs, and in a CORESET including three OFDM        symbols, an REG bundle includes 3 or 6 REGs. An REG bundle size        is configured on a CORESET basis.

System Information Acquisition

A UE may acquire AS-/NAS-information in the SI acquisition process. TheSI acquisition process may be applied to UEs in RRC_IDLE state,RRC_INACTIVE state, and RRC_CONNECTED state.

SI is divided into a master information block (MIB) and a plurality ofsystem information blocks (SIBs). The SI except for the MIB may bereferred to as remaining minimum system information (RMS) and othersystem information (OSI). RMSI corresponds to SIB1, and OSI refers toSIBs of SIB2 or higher other than SIB1. For details, reference may bemade to the followings.

-   -   The MIB includes information/parameters related to reception of        systemInformaitonBlockTypel (SIB1) and is transmitted on a PBCH        of an SSB. MIB information may include the following fields.    -   pdcch-ConfigSIB1: Determines a common ControlResourceSet        (CORESET), a common search space and necessary PDCCH parameters.        If the field ssb-SubcarrierOffset indicates that SIB1 is absent,        the field pdcch-ConfigSIB1 indicates the frequency positions        where the UE may find SS/PBCH block with SIB1 or the frequency        range where the network does not provide SS/PBCH block with        SIB1.    -   ssb-SubcarrierOffset: Corresponds to kSSB which is the frequency        domain offset between SSB and the overall resource block grid in        number of subcarriers. The value range of this field may be        extended by an additional most significant bit encoded within        PBCH. This field may indicate that this cell does not provide        SIB1 and that there is hence no CORESET #0 configured in MIB. In        this case, the field pdcch-ConfigSIB1 may indicate the frequency        positions where the UE may (not) find a SS/PBCH with a control        resource set and search space for SIB1.    -   subCarrierSpacingCommon: Subcarrier spacing for SIB1, Msg.2/4        for initial access, paging and broadcast SI-messages. If the UE        acquires this MIB on an FR1 carrier frequency, the value        scs15or60 corresponds to 15 kHz and the value scs30or120        corresponds to 30 kHz. If the UE acquires this MIB on an FR2        carrier frequency, the value scs15or60 corresponds to 60 kHz and        the value scs30or120 corresponds to 120 kHz.

In initial cell selection, the UE may determine whether there is acontrol resource set (CORESET) for a Type0-PDCCH common search spacebased on the MIB. The Type0-PDCCH common search space is a kind of aPDCCH search space, and is used to transmit a PDCCH scheduling an SImessage. In the presence of a Type0-PDCCH common search space, the UEmay determine (i) a plurality of consecutive RBs and one or moreconsecutive symbols in a CORESET and (ii) PDCCH occasions (i.e.,time-domain positions for PDCCH reception), based on information (e.g.,pdcch-ConfigSIB1) in the MIB. Specifically, pdcch-ConfigSIB1 is 8-bitinformation, (i) is determined based on the most significant bits (MSB)of 4 bits, and (ii) is determined based on the least significant bits(LSB) of 4 bits.

In the absence of any Type0-PDCCH common search space, pdcch-ConfigSIB1provides information about the frequency position of an SSB/SIB1 and afrequency range free of an SSB/SIB1.

For initial cell selection, a UE may assume that half frames withSS/PBCH blocks occur with a periodicity of 2 frames. Upon detection of aSS/PBCH block, the UE determines that a control resource set forType0-PDCCH common search space is present if k_(SSB)≤23 for FR1(Frequency Range 1; Sub-6 GHz; 450 to 6000 MHz) and if k_(SSB)≤11 forFR2 (Frequency Range 2; mm-Wave; 24250 to 52600 MHz). The UE determinesthat a control resource set for Type0-PDCCH common search space is notpresent if k_(SSB)>23 for FR1 and if k_(SSB)>11 for FR2. k_(SSB)represents a frequency/subcarrier offset between subcarrier 0 of SS/PBCHblock to subcarrier 0 of common resource block for SSB. For FR2 onlyvalues up to 11 are applicable. k_(SSB) may be signaled through theMIB.-SIB1 includes information related to the availability andscheduling (e.g., a transmission periodicity and an SI-window size) ofthe other SIBs (hereinafter, referred to as SIBx where x is an integerequal to or larger than 2). For example, SIB1 may indicate whether SIBxis broadcast periodically or provided by an UE request in an on-demandmanner. When SIBx is provided in the on-demand manner, SIB1 may includeinformation required for the UE to transmit an SI request. SIB1 istransmitted on a PDSCH, and a PDCCH scheduling SIB1 is transmitted in aType0-PDCCH common search space. SIB1 is transmitted on a PDSCHindicated by the PDCCH.

-   -   SIBx is included in an SI message and transmitted on a PDSCH.        Each SI message is transmitted within a time window (i.e., an        SI-window) which takes place periodically.

FIG. 6 illustrates exemplary multi-beam transmission of an SSB. Beamsweeping refers to changing the beam (direction) of a wireless signalover time at a transmission reception point (TRP) (e.g., a BS/cell)(hereinbelow, the terms beam and beam direction are interchangeablyused). An SSB may be transmitted periodically by beam sweeping. In thiscase, SSB indexes are implicitly linked to SSB beams. An SSB beam may bechanged on an SSB (index) basis. The maximum transmission number L of anSSB in an SSB burst set is 4, 8 or 64 according to the frequency band ofa carrier. Accordingly, the maximum number of SSB beams in the SSB burstset may be given according to the frequency band of a carrier asfollows.

-   -   For frequency range up to 3 GHz, Max number of beams=4    -   For frequency range from 3 GHz to 6 GHz, Max number of beams=8    -   For frequency range from 6 GHz to 52.6 GHz, Max number of        beams=64    -   Without multi-beam transmission, the number of SS/PBCH block        beams is 1.

When a UE attempts initial access to a BS, the UE may perform beamalignment with the BS based on an SS/PBCH block. For example, afterSS/PBCH block detection, the UE identifies a best SS/PBCH block.Subsequently, the UE may transmit an RACH preamble to the BS in PRACHresources linked/corresponding to the index (i.e., beam) of the bestSS/PBCH block. The SS/PBCH block may also be used in beam alignmentbetween the BS and the UE after the initial access.

FIG. 7 illustrates an exemplary method of indicating an actuallytransmitted SSB (SSB_tx). Up to L SS/PBCH blocks may be transmitted inan SS/PBCH block burst set, and the number/positions of actuallytransmitted SS/PBCH blocks may be different for each BS/cell. Thenumber/positions of actually transmitted SS/PBCH blocks are used forrate-matching and measurement, and information about actuallytransmitted SS/PBCH blocks is indicated as follows.

If the information is related to rate-matching: the information may beindicated by UE-specific RRC signaling or remaining minimum systeminformation (RMSI). The UE-specific RRC signaling includes a full bitmap(e.g., of length L) for frequency ranges below and above 6 GHz. The RMSIincludes a full bitmap for a frequency range below 6 GHz and acompressed bitmap for a frequency range above 6 GHz, as illustrated.Specifically, the information about actually transmitted SS/PBCH blocksmay be indicated by a group-bitmap (8 bits)+an in-group bitmap (8 bits).Resources (e.g., REs) indicated by the UE-specific RRC signaling or theRMSI may be reserved for SS/PBCH block transmission, and a PDSCH/PUSCHmay be rate-matched in consideration of the SS/PBCH block resources.

If the information is related to measurement: the network (e.g., BS) mayindicate an SS/PBCH block set to be measured within a measurementperiod, when the UE is in RRC connected mode. The SS/PBCH block set maybe indicated for each frequency layer. Without an indication of anSS/PBCH block set, a default SS/PBCH block set is used. The defaultSS/PBCH block set includes all SS/PBCH blocks within the measurementperiod. An SS/PBCH block set may be indicated by a full bitmap (e.g., oflength L) in RRC signaling. When the UE is in RRC idle mode, the defaultSS/PBCH block set is used.

Random Access Operation and Related Operation

When there is no PUSCH transmission resource (i.e., uplink grant)allocated by the BS, the UE may perform a random access operation.Random access of the NR system can occur 1) when the UE requests orresumes the RRC connection, 2) when the UE performs handover orsecondary cell group addition (SCG addition) to a neighboring cell, 3)when a scheduling request is made to the BS, 4) when the BS indicatesrandom access of the UE in PDCCH order, or 5) when a beam failure or RRCconnection failure is detected.

The RACH procedure of LTE and NR consists of 4 steps of Msg1 (PRACHpreamble) transmission from the UE, Msg2 (RAR, random access response)transmission from the BS, Msg3 (PUSCH) transmission from the UE, andMsg4 (PDSCH) transmission from the BS. That is, the UE transmits aphysical random access channel (PRACH) preamble and receives an RAR as aresponse thereto. When the preamble is a UE-dedicated resource, that is,in the case of contention free random access (CFRA), the random accessoperation is terminated by receiving the RAR corresponding to the UEitself. If the preamble is a common resource, that is, in the case ofcontention based random access (CBRA), after the RAR including an uplinkPUSCH resource and a RACH preamble ID (RAPID) selected by the UE isreceived, Msg3 is transmitted through a corresponding resource on thePUSCH. And after a contention resolution message is received on thePDSCH, the random access operation is terminated. In this case, a timeand frequency resources to/on which the PRACH preamble signal ismapped/transmitted is defined as RACH occasion (RO), and a time andfrequency resource to/on which the Msg3 PUSCH signal ismapped/transmitted is defined as PUSCH occasion (PO).

In Rel. 16 In NR and NR-U, a 2-step RACH procedure has been introduced,which is a reduced procedure for the 4-step RACH procedure. The 2-stepRACH procedure is composed of MsgA (PRACH preamble+Msg3 PUSCH)transmission from the UE and MsgB (RAR+Msg4 PDSCH) transmission from thegNB.

The PRACH format for transmitting the PRACH preamble in the NR systemconsists of a format composed of a length 839 sequence (named as a longRACH format for simplicity) and a format composed of a length 139sequence (named as a short RACH format for simplicity). For example, infrequency range 1 (FR1), the sub-carrier spacing (SCS) of the short RACHformat is defined as 15 or 30 kHz. Also, as shown in FIG. 8 , RACH canbe transmitted on 139 tones among 12 RBs (144 REs). In FIG. 8 , 2 nulltones are assumed for the lower RE index and 3 null tones are assumedfor the upper RE index, but the positions may be changed.

The above-mentioned short PRACH format comprises values defined in Table5. Here, is defined as one of {0, 1, 2, 3} according to the value ofsubcarrier spacing. For example, in the case of 15 kHz subcarrierspacing, μ is 0. In the case of 30 kHz subcarrier spacing, μ is 1. Table5 shows Preamble formats for LRA=139 and Δf^(RA)=15×2^(μ) kHz, whereμ∈{0,1,2,3}, κ=T_(s)/T_(c)=64.

TABLE 5 Format L_(RA) Δf^(RA) N_(u) N_(CP) ^(RA) A1 139 15 × 2^(μ) kHz 2× 2048κ × 2^(−μ) 288κ × 2^(−μ) A2 139 15 × 2^(μ) kHz 4 × 2048κ × 2^(−μ)576κ × 2^(−μ) A3 139 15 × 2^(μ) kHz 6 × 2048κ × 2^(−μ) 864κ × 2^(−μ) B1139 15 × 2^(μ) kHz 2 × 2048κ × 2^(−μ) 216κ × 2^(−μ) B2 139 15 × 2^(μ)kHz 4 × 2048κ × 2^(−μ) 360κ × 2^(−μ) B3 139 15 × 2^(μ) kHz 6 × 2048κ ×2^(−μ) 504κ × 2^(−μ) B4 139 15 × 2^(μ) kHz 12 × 2048κ × 2^(−μ)  936κ ×2^(−μ) C0 139 15 × 2^(μ) kHz 2048κ × 2^(−μ) 1240κ × 2^(−μ)  C2 139 15 ×2^(μ) kHz 4 × 2048κ × 2^(−μ) 2048κ × 2^(−μ) 

The BS can announce which PRACH format can be transmitted as much as aspecific duration at a specific timing through higher layer signaling(RRC signaling or MAC CE or DCI, etc.) and how many ROs (RACH occasionsor PRACH occasions) are in the slot. Table 6 shows a part of PRACHconfiguration indexes that can use A1, A2, A3, B1, B2, B3.

TABLE 6 N_(t) ^(RA, slot), Number of number of PRACH PRACH time-domainConfig- n_(SFN)mo slots PRACH occasions N_(dur) ^(RA), uration Preambled x = y Subframe Starting within a within a PRACH Index format x ynumber symbol subframe PRACH slot duration 81 A1 1 0 4.9 0 1 6 2 82 A1 10 7.9 7 1 3 2 100 A2 1 0 9 9 1 1 4 101 A2 1 0 9 0 1 3 4 127 A3 1 0 4.9 01 2 6 128 A3 1 0 7.9 7 1 1 6 142 B1 1 0 4.9 2 1 6 2 143 B1 1 0 7.9 8 1 32 221 A1/B1 1 0 4.9 2 1 6 2 222 A1/B1 1 0 7.9 8 1 3 2 235 A2/B2 1 0 4.90 1 3 4 236 A2/B2 1 0 7.9 6 1 2 4 251 A3/B3 1 0 4.9 0 1 2 6 252 A3/B3 10 7.9 2 1 2 6

Referring to Table 6, information about the number of ROs defined in aRACH slot for each preamble format (i.e., N_(t) ^(RA,slot): number oftime-domain PRACH occasions within a PRACH slot), and the number of OFDMsymbols occupied by each PRACH preamble for the preamble format (i.e.,N_(dur) ^(RA), PRACH duration) can be known. In addition, by indicatingthe starting symbol of the first RO, information about the time at whichthe RO starts in the RACH slot can also be provided. FIG. 9 shows theconfiguration of the ROs in the RACH slot according to the PRACHconfiguration index values shown in Table 6.

Random Access for UE with Specific Capability

In general, a UE accessing a cell should support a certain UEcapability. For example, in order to access an LTE cell, the UE shall beable to receive the MIB and SIB being broadcast for the cell by the basestation. There are several types of SIB, and since the SIB can betransmitted through a plurality of PRBs, the UE accessing the LTE cellshould have the capability to receive at least 20 MHz Bandwidth.

In order to access the NR cell, first, the UE should be able to receivethe MIB essentially through the SSB/PBCH transmitted on the initial DLBWP. And, even if the SSB/PBCH can be received, the UE has to checkwhether the corresponding cell is accessible according to the cellaccess information included in SIB1. To this end, the UE may checkwhether a CORESET for the Type0-PDCCH common search space exists basedon the MIB. When the Type0-PDCCH common search space exists, the UEdetermines CORSET #0 and a PDCCH opportunity based on information in theMIB (e.g., pdcch-ConfigSIB1). And SIB1 is received through the PDSCHindicated by the PDCCH received at the corresponding PDCCH opportunity.

Upon receiving the SIB, the UE needs to check various information todetermine whether the UE can access the cell, and if some informationdoes not satisfy the condition, the UE determines that the UE is notallowed to access the cell. For example, the maximum uplink bandwidthsupported by the UE has to be greater than or equal to the bandwidth ofthe initial UL BWP, and the maximum downlink bandwidth supported by theUE should be greater than or equal to the bandwidth of the initial DLBWP. If this is not satisfied, the corresponding cell is determined tobe an access-prohibited cell.

Meanwhile, a new type of UE with Reduced Capability will be supported byRel. 17 NR standard. These reduced capability UE can be called as R-UEsor UEs different from the existing REL-15 UEs. A UE other than the R-UEcan be referred to as a Normal UE (N-UE) for convenience.

Since the R-UE supports reduced UE capability than the existing UE, aproblem may occur in the cell access process. For example, the R-UE maynot receive the MIB through the initial DL BWP of the existing NR cell.Even though the R-UE may receive the MIB, the R-UE may not receive thePDCCH scheduling CORSET #0 or SIB1. The R-UE may have a maximum uplinkbandwidth or a maximum downlink bandwidth smaller than the bandwidth ofthe initial BWP supported by existing NR cells. Or, due to thenumerology (SCS) of the initial BWP of the existing cell, a pagingmessage transmitted by the base station cannot be received by the R-UEor the uplink RACH transmission for initial access cannot be performed.To this end, a general NR cell may be an access-prohibited cell forR-UE.

Meanwhile, for the following reasons, the base station may have toprovide a system information request method suitable for the R-UE fromthe initial access process. The base station cannot not know whether acorresponding UE in idle mode is R-UE or N-UE. If system information forthe R-UE is configured separately/differently from system informationfor existing UE, and the base station has received a system informationrequest from a UE in idle mode, the base station cannot determinewhether it is an R-UE's system information request or an N-UE's systeminformation request. Even if the system information is the same for R-UEand N-UR, there may be a case where the R-UE cannot receive the systeminformation transmitted to the existing UE. For example, if the R-UE hasfewer reception antennas than the existing UE, or if the R-UE is locatedin enhanced coverage, the system information transmission optimized forthe existing UE cannot be received at R-UR.

Therefore, in an embodiment of the present invention, when an R-UEhaving a specific capability performs initial cell access, a method isprovided for a base station operating the corresponding cell to provideproper system information (even in the case of R-UE's system informationrequest). For example, the base station may provide two or more RandomAccess Configurations for requesting specific system information in acell, and the UE may select the Initial UL BWP and/or Random AccessConfiguration according to its UE-capabilities and system information torequest. A method is proposed for UE to select, based on the selectionof initial UL BWP/Random Access Configuration, an (actual) Initial DLBWP from among a plurality of Initial DL BWPs (candidates), to receive acommon channel of the cell, and/or to receive, through the commonchannel, specific system information that was requested by the UE. Therandom access configuration may include one or more of a RACH Occasion(RO), a Random Access Resource and a Radom Access Preamble Identifier(RAPID), an Association Period Index, and the like. This method can beused for UE with reduced capability or UE that requires coverageenhancement. The UE may select a random access configuration which isconfigured separately from a random access configuration for a Normal-UE(N-UE), and may request system information or try Initial Access basedon the selected random access configuration.

Transmitter (e.g., Base Station)

In an embodiment of the present invention, when the R-UE cannot receivethe conventional SIB1, or the conventional SIB1 does not configured forthe R-UE, or the R-UE has to receive additional R-UE dedicated/specificinformation in addition to the conventional SIB1 information, the R-UEmay receive a new SIB1. In this way, a separate new SIB1 that can bereceived by the R-UE is denoted as R-SIB1 for convenience. R-SIB1 mayinclude all or part of configuration information included in theconventional SIB1, and may also include configuration informationdedicated to R-UE. The existing UE does not receive R-SIB1. However, ifR-SIB1 is not provided, the R-UE may receive the Normal SIB1. In thiscase, the R-UE may also receive additional transmission of the NormalSIB1 (e.g., additional transmissions for coverage enhancement).

In this case, from the viewpoint of the base station, a cell shouldsimultaneously operate two types of SIB1s (i.e., SIB1 and R-SIB1). Onetype of MIB is mapped to both types of SIB1s, or the MIB is mapped tothe Normal SIB1, and the Normal SIB1 may be mapped to R-SIB1. NormalSIB1 and R-SIB1 may include scheduling information (e.g., RRC parameterschedulingInfoList) that informs whether other SIBs are broadcast or notand the transmission periods of other SIBs.

In addition to SIB1, the base station may transmit SIBx for broadcastingsystem information. Various SIB types may exist in this SIBx, and one orseveral SIB types are transmitted through one SI message. One cell maysimultaneously operate Normal SIBx and new SIBx. The new SIBx mayinclude R-UE dedicated/specific information and/or information notapplicable to the existing UE (e.g., R-SIBx). For example, in the caseof SIB3 indicating infra-frequency cell reselection information, a cellmay transmit both the Normal SIB3 and R-SIB3. In this case, the NormalSIB3 may be used for the existing UE to perform cell reselection, andthe R-SIB3 may be used for the R-UE to perform cell reselection. If theNormal SIBx does not include R-UE dedicated/specific information or R-UEdedicated/specific information is included only in R-SIBx, thescheduling information of R-SIB1 informs whether R-SIBx is broadcast ornot and the transmission period of R-SIB1. The scheduling information ofthe Normal SIB1 may inform whether the Normal SIBx is broadcast or notand the transmission period.

The base station may determine whether to broadcast this SIBx accordingto the UE's request. Parameter si-BroadcastStatus of SIB1 informswhether STBx is being broadcast for N-UEs. Also, in an embodiment of thepresent invention, SIB or R-SIB1 may include R-si-BroadcastStatus forR-UE, and R-si-BroadcastStatus informs whether SIBx or R-SIBx for R-UEsis being broadcast.

The UE may trigger the RACH to request transmission of an SI messageincluding SIBx. The base station may configure a PRACH resource for SImessage transmission request through SIB1 or R-SIB1. For example, thePRACH resource configuration included in SIB1 may be configured as Table7.

TABLE 7 -- Configuration for Msg1 based SI Request SI-RequestConfig::=SEQUENCE { rach-OccasionsSI SEQUENCE { rach-ConfigSI RACH-ConfigGeneric,ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth, oneHalf, one,two, four, eight, sixteen} } OPTIONAL, -- Need R si-RequestPeriodENUMERATED {one, two, four, six, eight, ten, twelve, sixteen} OPTIONAL,-- Need R si-RequestResources SEQUENCE (SIZE (1..maxSI-Message)) OFSI-RequestResources } SI-RequestResources ::= SEQUENCE {ra-PreambleStartIndex INTEGER (0..63), ra-AssociationPeriodIndex INTEGER(0..15) OPTIONAL, -- Need R ra-ssb-OccasionMaskIndex INTEGER (0..15)OPTIONAL -- Need R } R-SI-RequestConfig::= SEQUENCE { rach-OccasionsSISEQUENCE { rach-ConfigSI RACH-ConfigGeneric, ssb-perRACH-OccasionENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight,sixteen} } OPTIONAL, -- Need R si-RequestPeriod ENUMERATED {one, two,four, six, eight, ten, twelve, sixteen} OPTIONAL, -- Need Rsi-RequestResources SEQUENCE (SIZE (1..maxSI-Message)) OFSI-RequestResources } SI-RequestResources ::= SEQUENCE {ra-PreambleStartIndex INTEGER (0..63), ra-AssociationPeriodIndex INTEGER(0..15) OPTIONAL, -- Need R ra-ssb-OccasionMaskIndex INTEGER (0..15)OPTIONAL -- Need R }

In Table 7, Si-RequestConfig is a PRACH resource configuration used bythe N-UE, and R-si-RequestConfig is a PRACH resource configuration usedby the R-UE. Therefore, when the R-UE transmits the RACH preamble on thePRACH resource according to the R-si-RequestConfig, the base station maydetermine that the SIBx (e.g., SIBx mapped to the corresponding resourceof the PRACH preamble) is requested by the R-UE. Meanwhile, when theRACH preamble is transmitted on the PRACH resource according to theSi-RequestConfig, the base station may determine that the SIBx (e.g.,SIBx mapped to the corresponding resource of the PRACH preamble) isrequested by the N-UE. In more detail, (i) rach-OccationSI defines aPRACH configuration for SI request, (ii) ssb-perRACH-Occasion indicatesthe number of SSB blocks associated with a PRACH Occasion, (iii)si-RequestPeriod indicates the number of Association Periods betweenPRACH resources for the SI request (Association Period denotes a minimumnumber of PRACH configuration periods required for every SSB beam to beassociated with a corresponding PRACH occasion at least once), and (iv)si-RequestResources indicates ra-PreambleStartIndex,ra-AssociationPeriodIndex and ra-ssb-OccasionMaskIndex for theSI-request. ra-AssociationPeriodIndex indicates a specific AssociationPeriod in which PRACH for SI request is allowed from among AssociationPeriods included in si-RequestPeriod.

The base station may transmit R-SIBx if determined that the R-UE hasrequested, and may transmit only the Normal SIBx if determined that theN-UE has requested. The R-SIBx may be transmitted during an SI windowdifferent from that of the Normal SIBx. Accordingly, the R-UE receivesthe R-SIBx by monitoring the SI window for the R-SIBx.

Meanwhile, the Normal SIBx may also include information corresponding toboth the R-UE and N-UE. In this case, scheduling information in theNormal SIB1 and scheduling information in the R-SIB1 may schedule thesame Normal SIBx. For example, in the case of SIB6 or SIB7 broadcastinga public warning message, scheduling information in the Normal SIB1 andscheduling information in R-SIB1 can schedule the same SIB6 or the sameSIB7. Alternatively, scheduling information in Normal SIB1 andscheduling information in R-SIB1 may schedule the same R-SIBx.

Receiver (UE)

The R-UE receives SIB1 or R-SIB1 after selecting a cell. When R-SIB1 istransmitted, the R-UE receives the R-SIB1, but if there is no R-SIB1transmission, the R-UE receives SIB1. The R-UE may obtain, through thereceived SIB1 or R-SIB1, R-UE-specific information (e.g., RRCparameters) below:

-   -   R-si-BroadcastStatus    -   R-si-RequestConfig    -   R-si-WindowLength

When R-si-BroadcastStatus indicates broadcast of SIBx or R-SIBx, R-UEmonitors PDCCH during SI window period according to R-si-WindowLengthwithout RACH and obtains DCI whose CRC is scrambled with SI-RNTI. TheSI-RNTI may be an R-UE dedicated SI-RNTI, and a value may be setdifferently from a value of SI-RNTI for N-UE. The UE receives SIBx orR-SIBx according to DCI information.

FIG. 10 illustrates an SIBx or R-SIBx request process of N-UE and R-UEaccording to an embodiment of the present invention.

R-UE can trigger/initiate the RACH procedure when R-si-BroadcastStatusindicates non-broadcast of SIBx or R-SIBx. The RACH transmitted by theR-UE may be configured through R-si-RequestConfig information. RACHconfiguration information includes SSB-per-RACH Occasion information(e.g., the number of SSBs associated with a corresponding RO), SIRequest Period, and SI Request Resource for each SI message. SI RequestResource indicating a specific SI message may include Random AccessPreamble Indexes, Random Access Association Period Index, and RandomAccess SSB Occasion Mask Index. The R-UE and the N-UE may transmit RACHbased on different SSB-per-RACH Occasions, different SI Request Periods,and/or different SI Request Resources for each SI message.

SI Request Period is a period in which the R-UE can perform RACHtransmission for an SI request, and includes one or a plurality ofra-AssociationPeriod. The R-UE transmits the SI request message in thetime period indicated by the ra-AssociationPeriodIndex configured forthe SI Request Period. In detail, PRACH transmission is performed in atime period indicated by ra-AssociationPeriodIndex based on the SIRequest Resource associated with SI request message to request. SIRequest Resource may be determined based on RAPIDs indicated byra-PreambleStartIndex and RO (RACH Occasion) allowed byra-ssb-OccasionMaskIndex.

The base station may configure the RACH resource as follows in order todistinguish the SI message requests from different types of UEs. Asdescribed below, R-UE may select a SI message (i.e., SI messageincluding SIBx to request), configure an RA association period and ROsbased on the selected SI message, and select an available RO(s) in theconfigured RA association period to perform PRACH transmission.

Proposal 1: For the same SI message request, the N-UE and the R-UE canbe configured with the same SI Request Period, and different ROs withina time period indicated by the same ra-AssociationPeriodIndex.

For example, an SI request period consisting of 10ra-AssociationPeriodIndex may be configured by a base station for aspecific SI message (e.g., SIBx) request, and the N-UE and R-UE may beconfigured with different ROs during the time period indicated by thesame ra-AssociationPeriodIndex of the same SI Request Period. In thiscase, the same or different RAPIDs are configured for the N-UE and theR-UE for a specific SI message.

Proposal 2: For the same SI message request, the N-UE and the R-UE canbe configured with the same SI Request Period, and the same RO positionwithin time Periods each indicated by differentra-AssociationPeriodIndex.

For example, an SI request period consisting of 10ra-AssociationPeriodIndex may be configured by a base station for aspecific SI message (e.g., SIBx) request, and the N-UE and R-UE may beconfigured with different ra-AssociationPeriodIndex of the same SIRequest Period. The (relative) position of the ROs (or the order of ROs)within the indicated time period. In this case, the same or differentRAPIDs are configured for the N-UE and the R-UE for the specific SImessage.

Proposal 3: For the same SI message request, the N-UE and the R-UE maybe configured with the same SI Request Period, and different ROs withintime periods each indicated by different ra-AssociationPeriodIndex.

For example, an SI request period consisting of 10ra-AssociationPeriodIndex may be configured by a base station for aspecific SI message (e.g., SIBx) request, and the N-UE and R-UE mayconfigure different ROs within time periods indicated by differentra-AssociationPeriodIndex of the same SI Request Period. In this case,the same or different RAPIDs are configured for the N-UE and the R-UEfor the specific SI message.

Proposal 4: For the same SI message request, the N-UE and the R-UE maybe configured with the same SI Request Period, and the same RO withinthe time period indicated by the same ra-AssociationPeriodIndex.

For example, an SI request period consisting of 10ra-AssociationPeriodIndex may be configured by a base station for aspecific SI message (e.g., SIBx) request, and the N-UE and R-UE mayconfigure the same ROs within a time interval indicated by the samera-AssociationPeriodIndex of the same SI Request Period. In this case,for the specific SI message, the N-UE and the R-UE aredistinguished/allocated with different RAPIDs.

Proposal 5: For the same SI message request, the N-UE and the R-UE maybe configured with different SI Request Periods.

For example, an SI request period composed of 5ra-AssociationPeriodIndex can be configured for the Normal UE, and an SIrequest period composed of 15 ra-AssociationPeriodIndex can beconfigured for the R-UE. For a specific SI message (e.g., SIBx) request,the N-UE and the R-UE may configure the same or different ROs within thetime period indicated by the same or different ra-AssociationPeriodIndexaccording to Proposal 1 or 2 or 3 or 4 above. In this case, the same ordifferent RAPIDs are configured for the N-UE and the R-UE for a specificSI message.

After the PRACH preamble is transmitted, the R-UE monitors the PDCCHthrough the RA window. When R-si-RequestConfig configures a DL BWP forPDCCH monitoring, the R-UE may perform PDCCH monitoring in a DL BWPdifferent from that of the N-UE. When DCI whose CRC is scrambled byRA-RNTI is received during the RA window, the R-UE receives PDSCHscheduled by DCI.

The DCI may include at least part of following information:

-   -   Frequency domain resource assignment    -   Time domain resource assignment—4 bits    -   VRB-to-PRB mapping—1 bit    -   Modulation and coding scheme—5 bits    -   TB scaling—2 bits    -   LSBs of SFN (system frame number)—2 bits for the DCI format 1_0        with CRC scrambled by MsgB-RNTI or RA-RNTI for operation in a        cell with shared spectrum channel access; 0 bit otherwise    -   Support of REDCAP UEs.

When the DCI whose CRC is scrambled with the RA-RNTI includes orindicates ‘support of REDCAP UEs’, the R-UE receives the PDSCH scheduledby the DCI. Otherwise, the R-UE does not receive the PDSCH scheduled byDCI.

The R-UE receives the PDSCH and receives a Random Access Response MACControl Element (RAR MAC CE) through the corresponding PDSCH. If the RARMAC CE includes the RACH preamble index (RAPID) which has beentransmitted by the R-UE, the R-UE determines that the RACH process issuccessful. If the RAR MAC CE does not include the RAPID which has beentransmitted by the R-UE, the R-UE may performs the RACH preambletransmission again.

On the other hand, when the RAR MAC CE includes the RAPID which has beentransmitted by the R-UE and includes the UL grant associated with theRAPID, the R-UE transmits the MSG3 PUSCH according to the UL grant.Through the PUSCH, the R-UE may transmit capability or device type ofthe R-UE. In this case, the base station may provide SIBx that isconfigured in consideration of the capability or device type of theR-UE.

After the RACH process is successfully completed, the R-UE may receiveSIBx or R-SIBx. A specific bit of DCI (e.g., System informationindicator for R-UEs) may indicate whether SIBx, R-SIBx, or both aretransmitted through PDSCH scheduled by DCI. The DCI may includeinformation indicating whether the R-UE (only), the N-UE (only), or alltypes of UEs should receive the PDSCH scheduled by DCI.

The DCI may include at least part of following information:

-   -   Frequency domain resource assignment    -   Time domain resource assignment—4 bits    -   VRB-to-PRB mapping—1 bit    -   Modulation and coding scheme—5 bits    -   Redundancy version—2 bits    -   System information indicator—1 bit    -   System information indicator for REDCAP UEs

The R-UE decodes the PDSCH according to the DCI, and obtains the SImessage (SIBx or R-SIBx). If R-SIBx is transmitted in a correspondingcell, R-UE should receive R-SIBx. If R-SIBx is not transmitted in thecorresponding cell, the R-UE can receive SIBx (instead). The R-UEdetermines whether R-SIBx is transmitted based on one or more of SIB1,R-SIB1, and the DCI.

In an embodiment of the present invention, the R-UE can efficientlyrequest system information. And, the R-UE with reduced UE capabilitythan the N-UE can obtain system information configured for the R-UEtype.

FIG. 11 illustrates a method of receiving a signal by a user equipmentin an embodiment of the present invention.

Referring to FIG. 11 , UE may receive a first system information block(SIB) including a system information (SI) request-related configurationincluding a physical random access channel (PRACH) configuration (B01).

UE may transmit a random access (RA) preamble for an SI request based onthe PRACH configuration (B05).

UE may receive, in response to the RA preamble for the SI request, asecond SIB different from the first SIB (B10).

The SI request-related configuration may include first informationrelated only to a first type UE with reduced capability to support asmaller bandwidth (BW) than a second type UE, and second informationthat is common for the first type UE and the second type UE.

The UE may be the first type UE and may perform the RA preambletransmission by determining a specific RA association period and aspecific RA occasion (RO) based on both of the first information and thesecond information in the SI request-related configuration.

The first information may include an RA association period index, andthe second information may include an SI request period. The SI requestperiod may include one or more RA association periods and the RAassociation period index may indicate the specific RA association periodfrom the one or more RA association periods in the SI request period.Each RA association period may denote a minimum number of PRACHconfiguration periods required for every synchronization signal block(SSB) to be associated with a corresponding RO at least once. Thespecific RA association period may be dedicated to the first type UE,and the SI request period may be shared between the first type UE andthe second type UE.

The first information may include information regarding the specific RO,and the second information may include an RA association period indexand an SI request period. The specific RO may be dedicated to the firsttype UE and the specific RA association period may be shared between thefirst type UE and the second type UE.

The first information may include an SI request period. A first SIrequest period may be configured for the first type UE and a second SIrequest period may be configured for the second type UE. The specific RAassociation period may be one of RA association periods included in thefirst SI request period.

The first SIB may be an SIB common for the first type UE and the secondtype UE, and the second SIB may be an SIB dedicated to the first typeUE.

The first SIB may be SIB1 and the second SIB may be SIBx, where ‘x’denotes an integer larger than 1.

FIG. 12 illustrates a communication system 1 applied to the presentdisclosure.

Referring to FIG. 12 , a communication system 1 applied to the presentdisclosure includes wireless devices, Base Stations (BSs), and anetwork. Herein, the wireless devices represent devices performingcommunication using Radio Access Technology (RAT) (e.g., 5G New RAT(NR)) or Long-Term Evolution (LTE)) and may be referred to ascommunication/radio/5G devices. The wireless devices may include,without being limited to, a robot 100 a, vehicles 100 b-1 and 100 b-2,an eXtended Reality (XR) device 100 c, a hand-held device 100 d, a homeappliance 100 e, an Internet of Things (IoT) device 100 f, and anArtificial Intelligence (AI) device/server 400. For example, thevehicles may include a vehicle having a wireless communication function,an autonomous driving vehicle, and a vehicle capable of performingcommunication between vehicles. Herein, the vehicles may include anUnmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may includean Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) deviceand may be implemented in the form of a Head-Mounted Device (HMD), aHead-Up Display (HUD) mounted in a vehicle, a television, a smartphone,a computer, a wearable device, a home appliance device, a digitalsignage, a vehicle, a robot, etc. The hand-held device may include asmartphone, a smartpad, a wearable device (e.g., a smartwatch or asmartglasses), and a computer (e.g., a notebook). The home appliance mayinclude a TV, a refrigerator, and a washing machine. The IoT device mayinclude a sensor and a smartmeter. For example, the BSs and the networkmay be implemented as wireless devices and a specific wireless device200 a may operate as a BS/network node with respect to other wirelessdevices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the A1 server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 13 illustrates wireless devices applicable to the presentdisclosure.

Referring to FIG. 13 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 12 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 14 illustrates another example of a wireless device applied to thepresent disclosure. The wireless device may be implemented in variousforms according to a use-case/service (refer to FIG. 14 ).

Referring to FIG. 14 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 13 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 13 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 13 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 12 ), the vehicles (100 b-1 and 100 b-2 of FIG. 12 ), the XRdevice (100 c of FIG. 12 ), the hand-held device (100 d of FIG. 12 ),the home appliance (100 e of FIG. 12 ), the IoT device (100 f of FIG. 12), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the A1server/device (400 of FIG. 12 ), the BSs (200 of FIG. 12 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 14 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

FIG. 15 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe implemented by a mobile robot, a car, a train, a manned/unmannedAerial Vehicle (AV), a ship, etc.

Referring to FIG. 15 , a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. 14 ,respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an Electronic Control Unit (ECU). The driving unit 140 a maycause the vehicle or the autonomous driving vehicle 100 to drive on aroad. The driving unit 140 a may include an engine, a motor, apowertrain, a wheel, a brake, a steering device, etc. The power supplyunit 140 b may supply power to the vehicle or the autonomous drivingvehicle 100 and include a wired/wireless charging circuit, a battery,etc. The sensor unit 140 c may acquire a vehicle state, ambientenvironment information, user information, etc. The sensor unit 140 cmay include an Inertial Measurement Unit (IMU) sensor, a collisionsensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor,a heading sensor, a position module, a vehicle forward/backward sensor,a battery sensor, a fuel sensor, a tire sensor, a steering sensor, atemperature sensor, a humidity sensor, an ultrasonic sensor, anillumination sensor, a pedal position sensor, etc. The autonomousdriving unit 140 d may implement technology for maintaining a lane onwhich a vehicle is driving, technology for automatically adjustingspeed, such as adaptive cruise control, technology for autonomouslydriving along a determined path, technology for driving by automaticallysetting a path if a destination is set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous driving vehicle 100may move along the autonomous driving path according to the driving plan(e.g., speed/direction control). In the middle of autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using A1technology, etc., based on the information collected from vehicles orautonomous driving vehicles and provide the predicted trafficinformation data to the vehicles or the autonomous driving vehicles.

FIG. 16 is a diagram illustrating a DRX operation of a UE according toan embodiment of the present disclosure.

The UE may perform a DRX operation in the afore-described/proposedprocedures and/or methods. A UE configured with DRX may reduce powerconsumption by receiving a DL signal discontinuously. DRX may beperformed in an RRC_IDLE state, an RRC_INACTIVE state, and anRRC_CONNECTED state. The UE performs DRX to receive a paging signaldiscontinuously in the RRC_IDLE state and the RRC_INACTIVE state. DRX inthe RRC_CONNECTED state (RRC_CONNECTED DRX) will be described below.

Referring to FIG. 16 , a DRX cycle includes an On Duration and anOpportunity for DRX. The DRX cycle defines a time interval betweenperiodic repetitions of the On Duration. The On Duration is a timeperiod during which the UE monitors a PDCCH. When the UE is configuredwith DRX, the UE performs PDCCH monitoring during the On Duration. Whenthe UE successfully detects a PDCCH during the PDCCH monitoring, the UEstarts an inactivity timer and is kept awake. On the contrary, when theUE fails in detecting any PDCCH during the PDCCH monitoring, the UEtransitions to a sleep state after the On Duration. Accordingly, whenDRX is configured, PDCCH monitoring/reception may be performeddiscontinuously in the time domain in the afore-described/proposedprocedures and/or methods. For example, when DRX is configured, PDCCHreception occasions (e.g., slots with PDCCH SSs) may be configureddiscontinuously according to a DRX configuration in the presentdisclosure. On the contrary, when DRX is not configured, PDCCHmonitoring/reception may be performed continuously in the time domain.For example, when DRX is not configured, PDCCH reception occasions(e.g., slots with PDCCH SSs) may be configured continuously in thepresent disclosure. Irrespective of whether DRX is configured, PDCCHmonitoring may be restricted during a time period configured as ameasurement gap.

Table 8 describes a DRX operation of a UE (in the RRC_CONNECTED state).Referring to Table 8, DRX configuration information is received byhigher-layer signaling (e.g., RRC signaling), and DRX ON/OFF iscontrolled by a DRX command from the MAC layer. Once DRX is configured,the UE may perform PDCCH monitoring discontinuously in performing theafore-described/proposed procedures and/or methods, as illustrated inFIG. 5 .

TABLE 8 Type of signals UE procedure 1^(st) step RRC signalling(MAC-Receive DRX configuration CellGroupConfig) information 2^(nd) Step MACCE((Long) DRX Receive DRX command command MAC CE) 3^(rd) Step — Monitora PDCCH during an on-duration of a DRX cycle

MAC-CellGroupConfig includes configuration information required toconfigure MAC parameters for a cell group. MAC-CellGroupConfig may alsoinclude DRX configuration information. For example, MAC-CellGroupConfigmay include the following information in defining DRX.

-   -   Value of drx-OnDurationTimer: defines the duration of the        starting period of the DRX cycle.    -   Value of drx-InactivityTimer: defines the duration of a time        period during which the UE is awake after a PDCCH occasion in        which a PDCCH indicating initial UL or DL data has been detected    -   Value of drx-HARQ-RTT-TimerDL: defines the duration of a maximum        time period until a DL retransmission is received after        reception of a DL initial transmission.    -   Value of drx-HARQ-RTT-TimerDL: defines the duration of a maximum        time period until a grant for a UL retransmission is received        after reception of a grant for a UL initial transmission.    -   drx-LongCycleStartOffset: defines the duration and starting time        of a DRX cycle.    -   drx-ShortCycle (optional): defines the duration of a short DRX        cycle.

When any of drx-OnDurationTimer, drx-InactivityTimer,drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is running, the UEperforms PDCCH monitoring in each PDCCH occasion, staying in the awakestate.

What is claimed is:
 1. A method of receiving a signal by a userequipment (UE) in a wireless communication system, the methodcomprising: receiving a first system information block (SIB) including asystem information (SI) request-related configuration including aphysical random access channel (PRACH) configuration; transmitting arandom access (RA) preamble for an SI request based on the PRACHconfiguration; and receiving, in response to the RA preamble for the SIrequest, a second SIB different from the first SIB, wherein the SIrequest-related configuration includes first information related only toa first type UE with reduced capability to support a smaller bandwidth(BW) than a second type UE, and second information that is common forthe first type UE and the second type UE, and wherein the UE is thefirst type UE and performs the RA preamble transmission by determining aspecific RA association period and a specific RA occasion (RO) based onboth of the first information and the second information in the SIrequest-related configuration.
 2. The method according to claim 1,wherein the first information includes an RA association period index,and the second information includes an SI request period.
 3. The methodaccording to claim 2, wherein the SI request period includes one or moreRA association periods and the RA association period index indicates thespecific RA association period from the one or more RA associationperiods in the SI request period.
 4. The method according to claim 3,wherein each RA association period denotes a minimum number of PRACHconfiguration periods required for every synchronization signal block(SSB) to be associated with a corresponding RO at least once.
 5. Themethod according to claim 2, wherein the specific RA association periodis dedicated to the first type UE, and the SI request period is sharedbetween the first type UE and the second type UE.
 6. The methodaccording to claim 1, wherein the first information includes informationregarding the specific RO, and the second information includes an RAassociation period index and an SI request period.
 7. The methodaccording to claim 6, wherein the specific RO is dedicated to the firsttype UE and the specific RA association period is shared between thefirst type UE and the second type UE.
 8. The method according to claim1, wherein the first information includes an SI request period.
 9. Themethod according to claim 8, wherein a first SI request period isconfigured for the first type UE and a second SI request period isconfigured for the second type UE.
 10. The method according to claim 9,wherein the specific RA association period is one of RA associationperiods included in the first SI request period.
 11. The methodaccording to claim 1, wherein the first SIB is an SIB common for thefirst type UE and the second type UE, and the second SIB is an SIBdedicated to the first type UE.
 12. The method according to claim 1,wherein the first SIB is SIB1 and the second SIB is SIBx, where ‘x’denotes an integer larger than
 1. 13. A non-transitory computer readablemedium recorded thereon program codes for performing the methodaccording to claim
 1. 14. A device for wireless communication, thedevice comprising: a memory configured to store instructions; and aprocessor configured to perform operations by executing theinstructions, the operations comprising: receiving a first systeminformation block (SIB) including a system information (SI)request-related configuration including a physical random access channel(PRACH) configuration; transmitting a random access (RA) preamble for anSI request based on the PRACH configuration; and receiving, in responseto the RA preamble for the SI request, a second SIB different from thefirst SIB, wherein the SI request-related configuration includes firstinformation related only to a first type device with reduced capabilityto support a smaller bandwidth (BW) than a second type device, andsecond information that is common for the first type device and thesecond type device, and wherein the device is the first type device andperforms the RA preamble transmission by determining a specific RAassociation period and a specific RA occasion (RO) based on both of thefirst information and the second information in the SI request-relatedconfiguration.
 15. The device according to claim 14, further comprising;a transceiver configured to transmit or receive a signal under controlof the processor.
 16. The device according to claim 15, wherein thedevice is a user equipment (UE) configured to perform 3rd generationpartnership project (3GPP)-based wireless communication.